I recently told my 70s-something walking group that I wanted to write about “retrieval disorder,” our shared problem with remembering names and dates, what we had just read and where, even what we had for dinner last night. Or, in my case, the subject of the column I wrote the day before.

One walking buddy suggested I call it delayed retrieval disorder. “It’s not that we can’t remember,” she said. “It just takes us longer, sometimes a lot longer, than it used to.” Then she wondered, “Is it really a disorder? Since it seems to happen to all of us, isn’t this just normal aging?”

Indeed it is, I’ve learned from recent reports, including one released last month by the Institute of Medicine. And it doesn’t mean we’re all headed down the road to dementia, although unchecked, cognitive changes with age can make it increasingly difficult to meet the demands of daily life, like shopping, driving, cooking and socializing.

I am painfully aware of increasingly frequent memory lapses, like where I left my cellphone or glasses. I searched the house the other day for a container of ice cream, only to finally find it in the microwave, where I had planned to soften it. Without a shopping list, I inevitably return from the store without something I really needed. And without a hide-a-key, I would routinely lock myself out of the house.

I was a terrific speller and walking thesaurus most of my life, but now routinely resort to an online dictionary and my computer’s ability to second-guess the word I’m trying to spell.

Although memory issues become more apparent in the Medicare years, gradual changes in cognitive function actually begin decades earlier, their effects usually masked by the brain’s excess of neurons and ability to lay down new connections throughout life.

AARP reassuringly writes in its Staying Sharp booklets, “As brain functions go, forgetting may be almost as important as remembering; it would be inefficient for our brains to try to retain every bit of information we’re exposed to throughout life.”

About a third of healthy older people have difficulty remembering facts, people, places and other things encountered daily, “yet a substantial number of 80-year-olds perform as well as people in their 30s on difficult memory tests,” AARP noted.

Nor are those who do less well cognitively suffering from a brain disease. “Just as you wouldn’t say that a marathon runner who slows down in his 80s has a motor disease, age-related cognitive decline isn’t necessarily pathological,” said Molly V. Wagster, chief of neurosciences at the National Institute on Aging. “We may just be slower to retrieve information, and slower to learn new things.”

Besides, Dr. Wagster told me, “the older brain retains plasticity; it’s capable of making adaptive changes. Certain regions of the brain operate in slightly different ways that may actually be better than at young ages.” Some of the changes, like depth of comprehension and wisdom gleaned through experience, are improvements that can compensate for less positive age-related effects, she said.

Denise C. Park, a psychologist at the University of Texas at Dallas,reports that while the brain’s “processing capacity” declines rather steadily from the 20s onward, “world knowledge,” including vocabulary, increases, at least into the 70s, when it seems to plateau. Still, it is important for people to recognize possibly pathological symptoms of cognitive impairment, like getting lost driving to a familiar place, having difficulty with finances, or failing to take medications correctly — deficits that warrant medical attention, Dr. Wagster said.

As AARP put it, “forgetting where you parked your car can happen to everyone occasionally, but forgetting what your car looks like may be cause for concern.”

Preventing cognitive decline that can interfere with quality of life is a far better option than trying to reverse it. The Institute of Medicine highlighted several actions everyone can take to maximize the chances of remaining cognitively sound well into the twilight years.

First and foremost, “be physically active.” Numerous studies have documented benefits to the brain as well as the body from regular exercise. For example, among 18,766 women ages 70 to 81 participating in the Nurses’ Health Study, those with the highest level of activity had a 20 percent lower risk of cognitive impairmentthan those who were least active.

Second, prevent or control cardiovascular risk factors, including high blood pressure, smoking, obesity and diabetes. What is good for the heart also appears to be good for the brain. A diet relatively low in fat, cholesterol and sugar and replete in antioxidant-rich vegetables and fish are likely to be protective, as are adequate levels of vitamin D.

Drink alcohol moderately, defined as one drink a day for women, two for men, or not at all. And get adequate sleep — a good seven hours a night — to keep neurons firing at top speed. Depression has a negative effect on cognition at all ages; if you suffer from it, get it treated.

Be well educated. Even if you missed out on a good education early in life, it is not too late to engage in intellectually stimulating activities, including taking courses online or at a local college, reading books, participating in discussion groups, and attending lectures and other cultural activities.

Dr. Park maintains that “cognitive engagement” — learning complex new tasks like quilting, crocheting or digital photography — can improve cognitive performance. But Dr. Wagster emphasized that cognitively stimulating activities should also be personally rewarding or meaningful, not frustrating or just busy work.

“Learning a new language can be very difficult later in life unless one has a compelling reason to do so,” Dr. Wagster said.

Finally, none of these measures may be helpful if they prevent you from being involved socially in leisure or volunteer activities. Social interaction is a strong predictor of healthy aging.